Fix test_authentication_when_tenant_is_disabled

Fixes bug 1099645

Change-Id: I31cbfc8a2b3679d30063e24b7608a70c6b60f979
diff --git a/tempest/tests/identity/admin/test_users.py b/tempest/tests/identity/admin/test_users.py
index 1423741..4c437ba 100644
--- a/tempest/tests/identity/admin/test_users.py
+++ b/tempest/tests/identity/admin/test_users.py
@@ -172,7 +172,6 @@
                           self.data.test_tenant)
 
     @attr(type='negative')
-    @unittest.skip('Until Bug 988920 is fixed')
     def test_authentication_when_tenant_is_disabled(self):
         # User's token for a disabled tenant should not be authenticated
         self.data.setup_test_user()
diff --git a/tempest/tests/identity/base.py b/tempest/tests/identity/base.py
index ce160da..8fee7ef 100644
--- a/tempest/tests/identity/base.py
+++ b/tempest/tests/identity/base.py
@@ -48,7 +48,7 @@
 
     def disable_tenant(self, tenant_name):
         tenant = self.get_tenant_by_name(tenant_name)
-        self.client.update_tenant(tenant['id'], tenant['description'], False)
+        self.client.update_tenant(tenant['id'], enabled=False)
 
     def get_user_by_name(self, name):
         _, users = self.client.get_users()